Various mechanisms are known in the art for attempting to maintain parallelism between relatively movable platens in a compression press or the like, during closing movement of the platens which may mount dies, tooling or the like thereon and operate on a workpiece or work material disposed in the die between the platens. Eccentric loading in such type presses are frequently encountered because of the high pressures developed between the platens as they close on the workpiece or material in the die or mold, and correspondingly eccentric forces are generally developed, resulting in non-parallelism between the platens. Non-parallelism of the platens causes defects in the products produced in the molds or dies, including surface defects, and often results in changes of the flow of the work material in the die or mold cavity. Also depending upon the construction of the press, these eccentric forces can cause damage to certain components of the press as well as causing undue wear on the dies or molds, or breakage thereof.
Most of the known mechanisms with which the applicant is familiar, for maintaining parallelism between the relatively movable platens of a compression press, comprise substantial amounts of electronic controls usually including electronic sensors and the like, for attempting to maintain parallelism between the platens as they close on a die in the press. Opening and closing of a compression press in which platens are not parallel results not only in binding and excessive wear on the dies and on the press, but also the electronic control systems and components thereof are subject to damage and generally require substantial maintenance.